jQuery(function($) {

	var foreSlides    = $('.fore-slide');
	var backSlides    = $('.back-slide');
	var activeSlide   = 0;
	var height        = $(window).height();
	var lastScrollTop = 0;

	$('.tile-text').data('locked', 0);

	$(window).scroll(function() {
		
		var scrollTop = $(window).scrollTop();
		
		if(scrollTop > lastScrollTop) {

			// auto tile open
			$('.tile-text').each(function() {
				
				$this = $(this);
				
				if($this.offset().top - scrollTop <= height - (height / 3) && $this.data('locked') != 1) {
					$this.trigger('mouseenter');
					$this.data('locked', 1);
				}
				
			});
			
			// show first text block
			if(activeSlide == 0 && foreSlides.eq(0).offset().top - scrollTop <= (height / 2)) {
				foreSlides.eq(0).find('.fore-text').toggleClass('show-elem');
				activeSlide = 1;
			}

			if(activeSlide == 1 && foreSlides.eq(0).offset().top - scrollTop + height <= (height / 2)) {
			
				foreSlides.eq(0).find('.fore-text').toggleClass('show-elem');
				foreSlides.eq(1).find('.fore-text').toggleClass('show-elem');

				backSlides.eq(0).toggleClass('show-elem');
				activeSlide = 2;	
			} else if(activeSlide == 2 && foreSlides.eq(1).offset().top - scrollTop + height <= (height / 2)) {
			
				foreSlides.eq(1).find('.fore-text').toggleClass('show-elem');
				foreSlides.eq(2).find('.fore-text').toggleClass('show-elem');
				
				backSlides.eq(0).toggleClass('back-slide-drop');
				
				backSlides.eq(1).toggleClass('show-elem');
				activeSlide = 3;
			} else if(activeSlide == 3 && foreSlides.eq(2).offset().top - scrollTop + height <= (height / 2)) {
			
				foreSlides.eq(2).find('.fore-text').toggleClass('show-elem');
				foreSlides.eq(3).find('.fore-text').toggleClass('show-elem');

				backSlides.eq(1).toggleClass('back-slide-drop');
				
				backSlides.eq(2).toggleClass('show-elem');
				activeSlide = 4;
			} else if(activeSlide == 4 && foreSlides.eq(3).offset().top - scrollTop + height <= (height / 2)) {
			
				foreSlides.eq(3).find('.fore-text').toggleClass('show-elem');
				foreSlides.eq(4).find('.fore-text').toggleClass('show-elem');

				backSlides.eq(2).toggleClass('back-slide-drop');
				
				backSlides.eq(3).toggleClass('show-elem');
				activeSlide = 5;
			} else if(activeSlide == 5 && foreSlides.eq(4).offset().top - scrollTop <= 0) {
			
				backSlides.eq(3).toggleClass('back-slide-drop');
				activeSlide = 6;
			
			}
			
		} else {

			// auto tile closing
			$('.tile-text').each(function() {
				
				$this = $(this);
				
				if($this.offset().top - scrollTop >= height - (height / 3) && $this.data('locked') == 1) {
					$this.data('locked', 0);
					$this.trigger('mouseleave');
				}
				
			});
			
			// hide first text block
			if(activeSlide == 1 && foreSlides.eq(0).offset().top - scrollTop >= (height / 2)) {
				foreSlides.eq(0).find('.fore-text').toggleClass('show-elem');
				activeSlide = 0;
			}
		
			if(activeSlide == 2 && foreSlides.eq(1).offset().top - scrollTop >= (height / 2)) {

				foreSlides.eq(0).find('.fore-text').toggleClass('show-elem');
				foreSlides.eq(1).find('.fore-text').toggleClass('show-elem');
				
				backSlides.eq(0).toggleClass('show-elem');
				activeSlide = 1;
			} else if(activeSlide == 3 && foreSlides.eq(2).offset().top - scrollTop >= (height / 2)) {
			
				foreSlides.eq(1).find('.fore-text').toggleClass('show-elem');
				foreSlides.eq(2).find('.fore-text').toggleClass('show-elem');

				backSlides.eq(0).toggleClass('back-slide-drop');

				backSlides.eq(1).toggleClass('show-elem');
				activeSlide = 2;
			} else if(activeSlide == 4 && foreSlides.eq(3).offset().top - scrollTop >= (height / 2)) {
			
				foreSlides.eq(2).find('.fore-text').toggleClass('show-elem');
				foreSlides.eq(3).find('.fore-text').toggleClass('show-elem');

				backSlides.eq(1).toggleClass('back-slide-drop');
				
				backSlides.eq(2).toggleClass('show-elem');
				activeSlide = 3;
			} else if(activeSlide == 5 && foreSlides.eq(4).offset().top - scrollTop >= (height / 2)) {
			
				foreSlides.eq(3).find('.fore-text').toggleClass('show-elem');
				foreSlides.eq(4).find('.fore-text').toggleClass('show-elem');

				backSlides.eq(2).toggleClass('back-slide-drop');
				
				backSlides.eq(3).toggleClass('show-elem');
				activeSlide = 4;
			} else if(activeSlide == 6 && foreSlides.eq(4).offset().top - scrollTop + height >= height) {
				backSlides.eq(3).toggleClass('back-slide-drop');
				activeSlide = 5;
			}
			
		}

		lastScrollTop = scrollTop;

	});
	
});